The present invention relates to an adsorbent suitable for use in an extracorporeal circulation treatment, to remove .beta..sub.2 -microglobulin (hereinafter referred to as ".beta..sub.2 -m") and immunoglobulin L-chain (hereinafter referred to as "L-chain") which are contained in a body fluid.
In recent years, many of patients who have been treated by dialysis for a long piriod suffer from carpal tunnel syndrome. "Carpal tunnel syndrome" is a disease attended with symptoms of paralysis of the median nerve due to compression of the median nerve at the part of carpal tunnel. Lately, it was found out that a .beta.-fibril-like amyloid protein called "AH" was deposited on the diseased part. Further, it was found out that a precursor protein corresponding to the amyloid is the .beta..sub.2 -m which is contained in the patient's blood. However, there hitherto has not been found an effective treatment, especially drug treatment.
.beta..sub.2 -m is a low molecular protein (M. W. 11,800) consisting of one hundred of amino acids. The separation method by means of membrane has been used to separate a component in blood or plasma rather selectively according to the size so far. However, there are such disadvantages in this method as useful proteins except .beta..sub.2 -m may be removed and as the amount of removed .beta..sub.2 -m is small. Therefore a more selective and effective way to remove a lot of .beta..sub.2 -m is desired.
The method for removing .beta..sub.2 -m by means of adsorbent has hardly been used so far. A few examples of adsorbent for purification of .beta..sub.2 -m are known, for instance, an immunoadsorbent in which an anti .beta..sub.2 -m antibody is immobilized onto its carrier, an adsorbent based on a principle of affinity chromatography in which concanavalin A is immobilized as a compound showing an affinity for .beta..sub.2 -m (hereinafter referred to as "ligand") onto its carrier, and the like. Although these adsorbents show a high selectivity for .beta..sub.2 -m, they are not practical for a treatment because of the problems such as expensive anti .beta..sub.2 -m antibody and ligands, for instance, concanavalin A, an unstability in preservation and a difficulty of sterilization.
On the other hand, there is a desease called amyloidosis attended with serious troubles, for example, insufficiency of organs such as heart and kidrey, disturbance of impulse conducting system, progressive dementia, cerebrovascular disease, nerve trouble and so on. Amyloidosis is caused by a deposition of amyloid on a blood vessel, a certain organ and so on. It is known that there are some types of amyloidosis, i.e., primary amyloidosis, secondary amyloidosis, familial amyloidosis, senile amyloidosis, and so on, and that the composition of proteins causing amyloidosis differs depending on the type of amyloidosis.
Primary amyloidosis is caused by a protein called "AH", and the precursor corresponding to deposited amyloid is supposed to be L-chain. However, there hitherto has not been found an effective treatment, especially drug treatment. L-chain is a low molecular protein (M. W. 23,000) consisting of two hundreds of amino acids in the form of monomer.
Besides the primaly amyloidosis, there are some diseases attended with an extraordinary product of L-chain. The typical diseases are multiple myeloma, macroglobulinemia or malignant lymphoma and the highly produced L-chain in these diseases is a cloned protein called Bence Jones protein (hereinafter referred to as "BJP"). Usually BJP is excreted into urine. At that time, it inhibits the reabsorption of other proteins, especially albumin, and causes a myeloma kidney syndrone. Also, there are many cases to cause amyloidosis at heart, kidney and so on as a result of a deposition of a lot of BJP in serum. Therefore, an effective method for removing BJP in serum is wanted. However, there has not been found a practical method for removing so far, as same as that for primary amyloidosis.
The object of the present invention is to solve the mentioned problems and to provide an inexpensive adsorbent for use in an extracorporeal circulation treatment which is able to adsorb and remove a lot of both .beta..sub.2 -m and L-chain.